CentOS 7 uses GCC 4.8.5 version which satisfies ngx_pagespeed 1.10+ and ngx_brotli mininum GCC requires of 4.8+. CentOS 6 uses GCC 4.4.7 and requires devtoolset-3 package's GCC 4.9. This update adds a new option to control devtoolset-3 GCC 4.9 usage on CentOS 7 via NGINX_DEVTOOLSETGCC='n' which is disabled by default. Nginx is compiled with GCC 4.9 instead of system GCC 4.8.5 on CentOS 7 when enabled via setting NGINX_DEVTOOLSETGCC='y' in persistent config file /etc/centminmod/custom_config.inc and then recompile nginx via centmin.sh menu option 4. This opens up the doors for future devtoolset-4 support for GCC 5.3 and so forth on CentOS systems.

Centmin Mod Nginx can be compiled with either GCC or Clang compilers and defaults to using Clang via CLANG='y' option in centmin.sh. You can override this and switch from default Clang to GCC compilers for Nginx via CLANG='n' variable set in persistent config file /etc/centminmod/custom_config.inc and then recompile nginx via centmin.sh menu option 4.

So basically for CentOS 7 to use GCC 4.9 via devtoolset-3, set in persistent config file /etc/centminmod/custom_config.inc the following variables:

Code (Text):

NGINX_DEVTOOLSETGCC='y'
CLANG='n'

then recompile nginx via centmin.sh menu option 4

Running command below will tell you what Nginx is compiled and built with